Ancient human relatives (hominins) used stone tools to help them eat animals more than 3 million years ago, scientists report in the journal Nature today.
Fossil rib bone of a cow-sized animal from more than 3 million years ago shows tool marks © Dikika Research Project
Fossilised animal bones with stone-tool-inflicted marks on them were uncovered in Ethiopia by an international team, led by Shannon McPherron at the Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
The find is the oldest evidence of stone tool use found so far. The fossils date to about 3.4 million years ago, 800,000 years earlier than the previous oldest evidence.
The marks would have been made by a prehuman species to cut and prepare meat and marrow for consumption.
Illustrated scene with ancient human relative Australopithecus afarensis
The team says they are linked with Australopithecus afarensis, the ancient group that may have led to modern humans and that includes the famous 3.2 million-year-old ‘Lucy’ specimen.
Professor Chris Stringer, human origins expert at the Natural History Museum comments on the research, 'If confirmed, these finds are important evidence of an earlier switch to meat consumption in ancient hominins.'
'However, to learn more about the behaviour involved it would be necessary to find associations of stone tools with the processed bones.
Stone tool marks on 3.4 million-year-old fossil rib from Ethiopia © Dikika Research Project
'Additionally, there are claims from Kenya of another hominin in this time period called Kenyanthropus platyops, so this was also a possible candidate for the hominin responsible for the bone modifications.'
The fossil finds come from the Dikika Research Project area in the Lower Awash Valley, Ethiopia, where many well-preserved animal and hominin fossils have previously been found, including those from A. afarensis.
The team analysed fossil bones found at the site using different scanning and microscopy methods to reveal more detail in the bone marks.
Fossil rib bone showing marks made by stone tools. Both images are Environmental Scanning Electron Microscopy (ESEM). © Dikika Research Project
They found that 2 fossils, one belonging to a goat-sized animal and the other to a cow-sized animal, had stone tool marks that had been made before the bones fossilised.
The markings show that a sharp stone tool was used to cut flesh from the femur, and a blunt stone tool used to strike the bone, probably to reach the marrow inside. There were also scraping marks on rib bones where flesh was stripped off.
The team say this is the earliest evidence for meat and marrow consumption in the human lineage.
There were no stone tools found with the bones. So, for now, the team don't know if A. afarensis found the tools or perhaps made them themselves.